In general, an indoor light of a construction is implemented by representatively installing a fluorescent lamp or a halogen lamp on a ceiling or a wall. The fluorescent lamp or the halogen lamp is universally utilized as an indoor lamp, while the fluorescent lamp or the halogen lamp has high power consumption and primarily provides only a unicolor light. In order to solve the high power consumption and monotony of the light, an LED light which shows lights having various colors at lower power consumption than the fluorescent lamp or the halogen lamp has been manufactured and released in recent years.
Meanwhile, with an increase in supply of the LED light, a research into light control using various sensors has been made in order to save energy. For example, an illumination sensor is installed while being separately separated from the light or installed on a ceiling surface while being integrated with the light to measure an illumination value and a light control device controls a dimming level of the light in a space by using the illumination value measured through the illumination sensor.
However, if illumination data on a floor is not collected through an illuminometer on the floor surface on which the light is installed or the illumination sensor on the floor, the illumination measurement value may significantly vary depending on an installation position (a ceiling where the light is installed and outside a light fixture) of the illumination sensor and a surrounding environment, and as a result, it is difficult to predict the accurate illumination value of the floor at a place where the light is installed.